Research on Temperature Stress of Large-Area Concrete Beam-Slab Structure

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1 Reearh on Teeraure Sre of Large-rea Conree Bea-Slab Sruure L Yan-yng Deuy Profeor De. of rheure and anageen ngneerng College of Shanx Unvery Tayuan. Chna bra: Large-rea Conree bea-lab Sruure anly ean he onolhally a onree ruure whoe lengh and wdh are ore han axu of he ruure n he ode. The nfluene of eeraure hange hrnkage and ree on ruure he key o olvng he roble. Through a raal engneerng Shrnkage and ree forula aord wh e reul are brough forward. The alulaon reul of hrnkage ran eeraure ran and rereed ran onde e reul and an be dreed o roje. Keyword: large-area onree bea-lab ruure ; hrnkage ; ree ; eeraure re ;. INTRODUCTION Jnheng Mueu area ore han 2 2 wo-floor frae ruure he ba olun ne ze 8 8. The buldng ze 64 28rae of oon renforng eel.2% rae of rereed renforng eel.4%. There a o-oured r along long-an. The rereed bar Φ j 5.2 ued and onneed by lnker. 2. TST The e anly re rule and ran rule of wo-floor large-area onree by eeraure hange and onree hrnkage and ree. The eeraure re baed on he eeraure dfferene beween ndoor and oudoor and eeraure obervaon of lab. When heroeer and ollaon ran-eer are ebeded n floor we ll ge he eeraure readng and frequeny a he e on. The ba auon of alulang onree re by eel-eer: he eel-eer ran a uh a around onree ran he onree ran gven by = [ N N ]/ α [ T ] 2. T ran of hrnkage μ he onree hrnkage value of e he onree hrnkage value of heory Td Fg. The e on layou Fg.2 The e and heory value

2 Where N T are eel-eer nner fore and onree eerure a age N and T are he eel-eer nal value afer ourng and ourng eeraure eel area whle eel-eer dearae equal o 4 2 he odulu of elay of eel 2 5 N/ 2 and α he oeffen of heral exanon.2-5. The heroeer and eel-eer are eeded along wo-floor long-an. The e on hown n Fg.. There are hree knd of eaon unlgh and uddenne eeraure dfferene n he eeraure hange. The eaon anly aken no aoun n large-area onree. ordng o e readng he axu and nu of he wo-floor 32 and 5 reevely. The floor eeraure a loe a weaher afer hree day. We regard he eeraure average a he weaher whou hea of hydraon. The weaher hange orreond o one funon rule. T = T o[2nπ / 365] 2.2 λ Where T he average eeraure value n a yearand T =T ax T n /2 eeraure oe n a year and =T ax T n /2 λ e fro eeraure reaon o he fr ax eeraure. 3. BSIC PRMTRSS The f u he ube oreve rengh average value a 28 day. naely f u =45Ma. The oreve rengh forula gven by vare a age and gven by f = f28 a b a=4.2 b= = Where 28 he odulu of elay of onree a 28 day gven by 5 28 = = 3.37 N / f u Wh he an body a r een oured n worke nde eel-eer and heroeer. The ran nlude hrnkage ran and eeraure hange ran. We ge he hrnkage ran f ubra he eeraure hange ran fro he e readng. Beaue of under he ae envronen he een and an ruure are ondered he ae hrnkage rule gven by = β 3.4 o

3 Coared wh he e hrnkage value he heory forula of h roje gven by 4 28 = To large-area floor for dfferen hae beween een and ruure he forula gven by 4 28 = CRP THORY When alulang he eeraure ree eeraure dfferene and he odulu of elay a key o alulaon. The hrnkage and ree of onree aken no aoun for endurng long erod eaon eeraure dfferene. The ree ha ran vare wh e durng onnuou loadng. Cree ran bgger -3 e han ela ran. The age-adjued effeve odulu of Tro-Bazan vald ehod whh alulae ree onerned wh long-erod and u o equaon n eeraure re and hrnkage. The onree ran = 4. e r The ran durng one-way onan re gven by = J 4.2 Where o non-re ran aued by hrnkage and eeraure J alled ree oeffen whh exre he u of ela and reee er onan re a fro. 4.3 = = J C = C 4.4 Where he odulu of elay a C alled ree degree whh exre ree er re. = [ C ] [ C ] d 4.5

4 [ ] = [ χ ] 4.6 [ ] = 4.7 = [ χ ] 4.8 alled he age-adjued effeve odulu χ alled old-aged oeffen. R alled relax oeffen gven by χ = R 4.9 Cree oeffen gven by = β 4. = β β 4. f RH In he early loadng ree bgger and e nerval e le. In he laer ree le and e nerval e bgger. 5. TMPRTUR STRSSS CLCULTION The hrnkage and eeraure dfferene wll aue ran. Therefore boh eeraure hange and hrnkage nfluene on ruure ondered. Swell agen reven fro early rakng and rereng a vald eaure o reven fro rakng. Wh he age loe of rere dereae gradually. We aue ha oon eel rere eel afer enon and onree have ae ran regard he eon an drbue unforly. We alulae agnude by ung hrnkage rere aon and eeraure dfferene reevely. Se he area of floor =bh he area of oon eel he area of rere P. 5.. Shrnkage ree Shrnkage re aued by hrnkage ran whh nreae gradually. Se onree begn hrnkage a rodue hrnkage a oal ran re. By equlbru of fore [ ] K L = 5.

5 Solvng and ung Hooke law gve ] [ γ = Teeraure ree The eeraure yle. If eeraure begn aon fro age j and ubeon alulae e age o re fro o an be exreed a ].2 [ ] [ = L K T T 5.3 ] [.2 T γ = 5.4 Toal ree n = = Prere Prere udden loadng whh dereae gradually under ree. lyng rere a e afer enon effeve rere e equlbru equaon exreed ] [ ] [ = L K 5.6 Solvng ] [ γ = 5.7 effeve oreon e = Coaron heory alulaon wh e value

6 ran μ eng value a No. ran n heory Td ran μ eng value a No.5-5 ran n heory Td Te value a No. and heory Te value a No.5 and heory ran μ -5 - eng value a No.2 ran n heory ran μ -5 - eng value a No.6 ran n heory Td Te value a No.2 and heory Td Te value a No.6 and heory ran μ -5 - eng value a No.3 ran n heory ran μ -5 - eng value a No.7 ran n heory Td Td Te value a No.3 and heory Te value a No.7 and heory ran μ -5 - eng value a No.4 ran n heory ran μ -5 - eng value a No.8 ran n heory Td Te value a No.4 and heory Td Te value a No.8 and heory Fg.3 Curve of e value and heory alulaon The ze of eeraure re dede wheher rak or no. The re drbuon de-an le and ddle-an bg. In Fgure 4 he ax enle re of e on 7.2MPa The ax enle re of e

7 on 8.7MPa le han enle rengh of C4. I afe II-level an-rak deand. re MPa re MPa Ty Ty 292 No.7 re urve No.8 re urve Fg.4 Te on re urve 6. CONCLUSION Seaon eeraure rled by year ha eeraure re u be ubeon alulaon. Shrnkage ngle-way hange. Boh of he alulaed reevely and hen ung. The heory analy whou eeraure jon o olve eeraure re reaonable. RFRNCS Zhu Bofang Theral Sree and Teeraure Conrol of Ma Conree [M]. Bejng: Chna ler Power Pre 998 Teng Zhng Ba oonen of onree [M]. Bejng: Qnghua Unvery Pre 987 Guo Zhenha Conree Theory [M]. Bejng: Qnghua Unvery Pre 999 Z.P. Bazan and Jenn Chuan Chern. Bayean aal redon of onree ree and hrnkage. CI Journal July ugu Zhou Lu Chen Yonghun [M]. Bejng: Chna Ralway Pre 994. Madouh lbadry n Ghal. Conrol of Theral Crakng of Conree Sruure. CI Journal July ugu